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author | Dan Goodliffe <dan@randomdan.homeip.net> | 2021-01-17 19:36:30 +0000 |
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committer | Dan Goodliffe <dan@randomdan.homeip.net> | 2021-01-17 22:16:48 +0000 |
commit | 0bf4ad9e4a9e1c97e92aa23a365405dfef89bd7c (patch) | |
tree | 68a80976a247836bbb1eecc835af437e3489fbb7 /gfx/models/obj_loader.cpp | |
parent | First cut modernizing and sanitizing (diff) | |
download | ilt-0bf4ad9e4a9e1c97e92aa23a365405dfef89bd7c.tar.bz2 ilt-0bf4ad9e4a9e1c97e92aa23a365405dfef89bd7c.tar.xz ilt-0bf4ad9e4a9e1c97e92aa23a365405dfef89bd7c.zip |
Big reshuffle
Fixes code quality warnings now picked up.
Diffstat (limited to 'gfx/models/obj_loader.cpp')
-rw-r--r-- | gfx/models/obj_loader.cpp | 428 |
1 files changed, 428 insertions, 0 deletions
diff --git a/gfx/models/obj_loader.cpp b/gfx/models/obj_loader.cpp new file mode 100644 index 0000000..7611a2c --- /dev/null +++ b/gfx/models/obj_loader.cpp @@ -0,0 +1,428 @@ +#include "obj_loader.h" +#include <algorithm> +#include <fstream> +#include <map> +#include <memory> +#include <stdexcept> +#include <utility> + +static bool CompareOBJIndexPtr(const OBJIndex * a, const OBJIndex * b); +static inline unsigned int FindNextChar(unsigned int start, const char * str, unsigned int length, char token); +static inline unsigned int ParseOBJIndexValue(const std::string & token, unsigned int start, unsigned int end); +static inline float ParseOBJFloatValue(const std::string & token, unsigned int start, unsigned int end); +static inline std::vector<std::string> SplitString(const std::string & s, char delim); + +OBJModel::OBJModel(const std::string & fileName) +{ + hasUVs = false; + hasNormals = false; + std::ifstream file; + file.open(fileName.c_str()); + + std::string line; + if (file.is_open()) { + while (file.good()) { + getline(file, line); + + unsigned int lineLength = line.length(); + + if (lineLength < 2) { + continue; + } + + const char * lineCStr = line.c_str(); + + switch (lineCStr[0]) { + case 'v': + switch (lineCStr[1]) { + case 't': + this->uvs.push_back(ParseOBJVec2(line)); + break; + case 'n': + this->normals.push_back(ParseOBJVec3(line)); + break; + case ' ': + case '\t': + this->vertices.push_back(ParseOBJVec3(line)); + } + break; + case 'f': + CreateOBJFace(line); + break; + default: + break; + }; + } + } + else { + throw std::runtime_error {"Unable to load mesh: " + fileName}; + } +} + +void +IndexedModel::CalcNormals() +{ + for (unsigned int i = 0; i < indices.size(); i += 3) { + int i0 = indices[i]; + int i1 = indices[i + 1]; + int i2 = indices[i + 2]; + + glm::vec3 v1 = positions[i1] - positions[i0]; + glm::vec3 v2 = positions[i2] - positions[i0]; + + glm::vec3 normal = glm::normalize(glm::cross(v1, v2)); + + normals[i0] += normal; + normals[i1] += normal; + normals[i2] += normal; + } + + for (unsigned int i = 0; i < positions.size(); i++) { + normals[i] = glm::normalize(normals[i]); + } +} + +IndexedModel +OBJModel::ToIndexedModel() +{ + IndexedModel result; + IndexedModel normalModel; + + unsigned int numIndices = OBJIndices.size(); + + std::vector<OBJIndex *> indexLookup; + + for (unsigned int i = 0; i < numIndices; i++) { + indexLookup.push_back(&OBJIndices[i]); + } + + std::sort(indexLookup.begin(), indexLookup.end(), CompareOBJIndexPtr); + + std::map<OBJIndex, unsigned int> normalModelIndexMap; + std::map<unsigned int, unsigned int> indexMap; + + for (unsigned int i = 0; i < numIndices; i++) { + OBJIndex * currentIndex = &OBJIndices[i]; + + glm::vec3 currentPosition = vertices[currentIndex->vertexIndex]; + glm::vec2 currentTexCoord; + glm::vec3 currentNormal; + + if (hasUVs) { + currentTexCoord = uvs[currentIndex->uvIndex]; + } + else { + currentTexCoord = glm::vec2(0, 0); + } + + if (hasNormals) { + currentNormal = normals[currentIndex->normalIndex]; + } + else { + currentNormal = glm::vec3(0, 0, 0); + } + + unsigned int normalModelIndex; + unsigned int resultModelIndex; + + // Create model to properly generate normals on + const auto it = normalModelIndexMap.find(*currentIndex); + if (it == normalModelIndexMap.end()) { + normalModelIndex = normalModel.positions.size(); + + normalModelIndexMap.insert(std::pair<OBJIndex, unsigned int>(*currentIndex, normalModelIndex)); + normalModel.positions.push_back(currentPosition); + normalModel.texCoords.push_back(currentTexCoord); + normalModel.normals.push_back(currentNormal); + } + else { + normalModelIndex = it->second; + } + + // Create model which properly separates texture coordinates + unsigned int previousVertexLocation = FindLastVertexIndex(indexLookup, currentIndex, result); + + if (previousVertexLocation == (unsigned int)-1) { + resultModelIndex = result.positions.size(); + + result.positions.push_back(currentPosition); + result.texCoords.push_back(currentTexCoord); + result.normals.push_back(currentNormal); + } + else { + resultModelIndex = previousVertexLocation; + } + + normalModel.indices.push_back(normalModelIndex); + result.indices.push_back(resultModelIndex); + indexMap.insert(std::pair<unsigned int, unsigned int>(resultModelIndex, normalModelIndex)); + } + + if (!hasNormals) { + normalModel.CalcNormals(); + + for (unsigned int i = 0; i < result.positions.size(); i++) { + result.normals[i] = normalModel.normals[indexMap[i]]; + } + } + + return result; +}; + +unsigned int +OBJModel::FindLastVertexIndex( + const std::vector<OBJIndex *> & indexLookup, const OBJIndex * currentIndex, const IndexedModel & result) +{ + unsigned int start = 0; + unsigned int end = indexLookup.size(); + unsigned int current = (end - start) / 2 + start; + unsigned int previous = start; + + while (current != previous) { + OBJIndex * testIndex = indexLookup[current]; + + if (testIndex->vertexIndex == currentIndex->vertexIndex) { + unsigned int countStart = current; + + for (unsigned int i = 0; i < current; i++) { + OBJIndex * possibleIndex = indexLookup[current - i]; + + if (possibleIndex == currentIndex) { + continue; + } + + if (possibleIndex->vertexIndex != currentIndex->vertexIndex) { + break; + } + + countStart--; + } + + for (unsigned int i = countStart; i < indexLookup.size() - countStart; i++) { + OBJIndex * possibleIndex = indexLookup[current + i]; + + if (possibleIndex == currentIndex) { + continue; + } + + if (possibleIndex->vertexIndex != currentIndex->vertexIndex) { + break; + } + else if ((!hasUVs || possibleIndex->uvIndex == currentIndex->uvIndex) + && (!hasNormals || possibleIndex->normalIndex == currentIndex->normalIndex)) { + glm::vec3 currentPosition = vertices[currentIndex->vertexIndex]; + glm::vec2 currentTexCoord; + glm::vec3 currentNormal; + + if (hasUVs) { + currentTexCoord = uvs[currentIndex->uvIndex]; + } + else { + currentTexCoord = glm::vec2(0, 0); + } + + if (hasNormals) { + currentNormal = normals[currentIndex->normalIndex]; + } + else { + currentNormal = glm::vec3(0, 0, 0); + } + + for (unsigned int j = 0; j < result.positions.size(); j++) { + if (currentPosition == result.positions[j] + && ((!hasUVs || currentTexCoord == result.texCoords[j]) + && (!hasNormals || currentNormal == result.normals[j]))) { + return j; + } + } + } + } + + return -1; + } + else { + if (testIndex->vertexIndex < currentIndex->vertexIndex) { + start = current; + } + else { + end = current; + } + } + + previous = current; + current = (end - start) / 2 + start; + } + + return -1; +} + +void +OBJModel::CreateOBJFace(const std::string & line) +{ + std::vector<std::string> tokens = SplitString(line, ' '); + + this->OBJIndices.push_back(ParseOBJIndex(tokens[1], &this->hasUVs, &this->hasNormals)); + this->OBJIndices.push_back(ParseOBJIndex(tokens[2], &this->hasUVs, &this->hasNormals)); + this->OBJIndices.push_back(ParseOBJIndex(tokens[3], &this->hasUVs, &this->hasNormals)); + + if ((int)tokens.size() > 4) { + this->OBJIndices.push_back(ParseOBJIndex(tokens[1], &this->hasUVs, &this->hasNormals)); + this->OBJIndices.push_back(ParseOBJIndex(tokens[3], &this->hasUVs, &this->hasNormals)); + this->OBJIndices.push_back(ParseOBJIndex(tokens[4], &this->hasUVs, &this->hasNormals)); + } +} + +OBJIndex +OBJModel::ParseOBJIndex(const std::string & token, bool * hasUVs, bool * hasNormals) +{ + unsigned int tokenLength = token.length(); + const char * tokenString = token.c_str(); + + unsigned int vertIndexStart = 0; + unsigned int vertIndexEnd = FindNextChar(vertIndexStart, tokenString, tokenLength, '/'); + + OBJIndex result { + .vertexIndex = ParseOBJIndexValue(token, vertIndexStart, vertIndexEnd), + .uvIndex = 0, + .normalIndex = 0, + }; + + if (vertIndexEnd >= tokenLength) { + return result; + } + + vertIndexStart = vertIndexEnd + 1; + vertIndexEnd = FindNextChar(vertIndexStart, tokenString, tokenLength, '/'); + + result.uvIndex = ParseOBJIndexValue(token, vertIndexStart, vertIndexEnd); + *hasUVs = true; + + if (vertIndexEnd >= tokenLength) { + return result; + } + + vertIndexStart = vertIndexEnd + 1; + vertIndexEnd = FindNextChar(vertIndexStart, tokenString, tokenLength, '/'); + + result.normalIndex = ParseOBJIndexValue(token, vertIndexStart, vertIndexEnd); + *hasNormals = true; + + return result; +} + +glm::vec3 +OBJModel::ParseOBJVec3(const std::string & line) +{ + unsigned int tokenLength = line.length(); + const char * tokenString = line.c_str(); + + unsigned int vertIndexStart = 2; + + while (vertIndexStart < tokenLength) { + if (tokenString[vertIndexStart] != ' ') { + break; + } + vertIndexStart++; + } + + unsigned int vertIndexEnd = FindNextChar(vertIndexStart, tokenString, tokenLength, ' '); + + float x = ParseOBJFloatValue(line, vertIndexStart, vertIndexEnd); + + vertIndexStart = vertIndexEnd + 1; + vertIndexEnd = FindNextChar(vertIndexStart, tokenString, tokenLength, ' '); + + float y = ParseOBJFloatValue(line, vertIndexStart, vertIndexEnd); + + vertIndexStart = vertIndexEnd + 1; + vertIndexEnd = FindNextChar(vertIndexStart, tokenString, tokenLength, ' '); + + float z = ParseOBJFloatValue(line, vertIndexStart, vertIndexEnd); + + return glm::vec3(x, y, z); +} + +glm::vec2 +OBJModel::ParseOBJVec2(const std::string & line) +{ + unsigned int tokenLength = line.length(); + const char * tokenString = line.c_str(); + + unsigned int vertIndexStart = 3; + + while (vertIndexStart < tokenLength) { + if (tokenString[vertIndexStart] != ' ') { + break; + } + vertIndexStart++; + } + + unsigned int vertIndexEnd = FindNextChar(vertIndexStart, tokenString, tokenLength, ' '); + + float x = ParseOBJFloatValue(line, vertIndexStart, vertIndexEnd); + + vertIndexStart = vertIndexEnd + 1; + vertIndexEnd = FindNextChar(vertIndexStart, tokenString, tokenLength, ' '); + + float y = ParseOBJFloatValue(line, vertIndexStart, vertIndexEnd); + + return glm::vec2(x, y); +} + +static bool +CompareOBJIndexPtr(const OBJIndex * a, const OBJIndex * b) +{ + return a->vertexIndex < b->vertexIndex; +} + +static inline unsigned int +FindNextChar(unsigned int start, const char * str, unsigned int length, char token) +{ + unsigned int result = start; + while (result < length) { + result++; + if (str[result] == token) { + break; + } + } + + return result; +} + +static inline unsigned int +ParseOBJIndexValue(const std::string & token, unsigned int start, unsigned int end) +{ + return std::stoul(token.substr(start, end - start)) - 1; +} + +static inline float +ParseOBJFloatValue(const std::string & token, unsigned int start, unsigned int end) +{ + return std::stof(token.substr(start, end - start)); +} + +static inline std::vector<std::string> +SplitString(const std::string & s, char delim) +{ + std::vector<std::string> elems; + + const char * cstr = s.c_str(); + unsigned int strLength = s.length(); + unsigned int start = 0; + unsigned int end = 0; + + while (end <= strLength) { + while (end <= strLength) { + if (cstr[end] == delim) { + break; + } + end++; + } + + elems.push_back(s.substr(start, end - start)); + start = end + 1; + end = start; + } + + return elems; +} |